JACKSON, Wyo. — After a weekend of cooler and wetter conditions, the weather pattern will turn decidedly mild heading into the first week of October. “Indian Summer” will be in full force with sunny skies and warm temperatures (well into the 70s for highs most days) expected through the first 10 days of October.
The emerging pattern looks completely different from this time last year, when snow and cold temperatures arrived during the first few days of October, setting the stage for what ended up being the coldest October on record in Jackson Hole.
October to begin with mild weather this year
There was a definite fall-like chill over Jackson Hole this past weekend and especially on Monday morning when clearing skies allowed the temperature to plummet to 19 degrees at the Jackson Hole Airport — the coldest temperature of the fall season so far.
However, the cold snap will be short lived. A strong ridge of high pressure will build over the Western U.S. this week and will remain in place for the better part of two weeks.
The result? Little to no precipitation is projected through the first 10 days of October and temperatures will be consistently above average with highs in the 70s. This will likely be our last extended stretch of 70-degree weather until next spring, so enjoy it while it lasts!
Keep in mind that with high pressure, clear skies and light winds in place, there will be large day-to-night temperature swings with valley lows falling into the 20s most nights.
The European Model ensemble runs are projecting little to no precipitation over the next 10 days not only in Jackson Hole, but across nearly the entire Western U.S. other than the Pacific Northwest.
Wildfires continue to burn across the Western U.S.
While the extended “Indian summer” weather will be wonderful in Jackson Hole for outdoor adventures — especially as the fall colors are peaking — the continued stretch of warm and dry weather will not be such a good thing in other parts of the west.
Large wildfires continue to burn across California with no rain in sight there, and in Wyoming, the Mullen Fire in Medicine Bow National Forest outside of Laramie exploded to at least 80,000 acres over the weekend and is threatening numerous structures. Fires are currently active in Utah and Colorado as well.
As for smoke issues in Jackson Hole, we shouldn’t seen any of it through at least Friday. However, the farther out in time we get, there is a possibility we could eventually see some smoke from California arrive — though it would likely not be nearly as thick compared to what we have experienced at times during the past six weeks.
How long will the warm and dry pattern last?
After a dry start to October, signs are now emerging that we could enter a more active pattern starting sometime in the October 10-15 range. Whether or not this is a temporary pattern change or prolonged pattern change remains to be seen.
Preliminary September Review
We are still a few days away from the end of September, but will likely finish the month with slightly warmer than average temperatures and slightly below average precipitation.
Through September 27, temperatures at the Jackson Hole Airport are running 1.1 degrees above average for the month. Temperatures have ranged from a high of 90 on September 5 to a low of 19 on September 28 (today). The town weather station (where precipitation readings are more reliable) has recorded 1.17 inches of precipitation this month, which is below the 30-year average of 1.51 inches.
It’s been an interesting month to say the least — for most of the month, the pattern has been very quiet. However, the exceptions were notable, especially the Labor Day storm that brought damaging winds and an early snow to the valley floor.
A line of strong thunderstorms on September 19 as well as this past weekend’s cold front kept things just interesting enough for the rest of the month, while we managed to avoid any major high elevation snows that could have prematurely shut down high elevation hiking season. Instead, most of the high elevation trails will be in good shape through early October this year.
Note: I will be out of town for all of next week, so my next weekly weather article will not be posted until Monday, October 12
Alan Smith, Meteorologist, jacksonholeweatherforecast.com
